I'm surprised you mention this one, as I've had absolutely terrible service from UA at ATL. Once at the UC, agent stared at my Lufthansa boarding pass long and hard, scanned it and huffed saying "I *guess* you can enjoy the lounge". The second instance with a different agent was late at night I wanted a gate pass to get my grandparents from the gate, she first refused a gate pass, then tried lying to me that the flight already landed, then yelling "I'M LOOKIN AT IT" when I offered to show her FR24 that the flight most definitely didn't land. Eventually I had the pass issued but her having the title of "Service Director" and behaving like this is APPALLING.